ABSTRACT
Mechanical factors60 Immune responses 61 Invasion by phagocytic cells 61 Parenchymal invasion by pleural mesothelial cells 62
Pleural inflammatory cells62 Neutrophils 62
Mononuclear cells 62 Eosinophils 62
Initiation of inflammation 63 Perpetuation of inflammation63 Resolution and repair 64 Inhibition of pleural inflammatory responses 64 References 65
e pleural mesothelium is a monolayer of cells that may vary from a attened, ovoid shape to columnar or cuboidal cells that lie loosely over the underlying substructure.1 A unique characteristic of the pleural space is that it is a potential space within a closed environment. Although there are lymphatic connections into the pleural space, these are not present in extensive numbers and may change in number and size depending on need.2 e lymph nodes that drain pleural structures include the mediastinal, intercostal, and sternal lymph nodes. e connective tissue in the basement membrane of the pleura is a complex structure that underlies the surface layer of mesothelial cells and plays an important role in inammation of the pleural space.3 A large meshwork of capillaries that originates from the bronchial arterial vessels is present in the subpleural layer. e parietal
and diaphragmatic surface of the pleura is supplied by local blood vessels to those areas. e volume of pleural uid in the pleural space remains very small, in the range of 0.2-0.5 mL. e protein content is low and the cellular content is also low with an absence of inammatory cells.4
